So-called xe2x80x9cfoldingxe2x80x9d analog-to-digital converters (ADC""s) are well known in the art. Folding ADC""s convert analog signals to corresponding digital signals by generating an output signal that is typically a piecewise-linear periodic function of an input signal. The output of such a device is therefore xe2x80x9cfoldedxe2x80x9d and can have a substantially smaller dynamic range than its corresponding input signal. As a consequence, a folding ADC is preferred over conventional xe2x80x9cflashxe2x80x9d or parallel converters in that the folded waveform can be digitized utilizing substantially fewer comparators. A folding ADC therefore consumes less power and is also useful for high speed data communication and storage applications.
The limitations and inadequacies of conventional folding analog-to-digital converters (ADC""s) are substantially overcome by the present invention, in which a principal object is to provide a folding analog-to-digital converter (ADC) having a minimal number of voltage comparators.
Still another object of the present invention to provide a folding ADC characterized by low power consumption and which outputs a periodic function representative of an analog input signal.
Yet another object of the present invention to provide a folding ADC for use in high speed data communication and storage applications.
Accordingly, an electronic circuit is provided having: a first differential amplifier circuit having a first reference voltage; a second differential amplifier circuit coupled to the first differential amplifier circuit, the second differential amplifier circuit can a second reference voltage; and a resistive network coupled to the first having a second differential amplifier circuits.
In addition, the electronic circuit is provided having a third differential amplifier circuit coupled to the first and second differential amplifier circuits for regulating the flow of current through one of the differential amplifier circuits at any given time, such that the periodic function has a first zero-crossing when the voltage of the analog input signal equals the first reference voltage and a second zero-crossing when the voltage of the analog input signal equals the second reference voltage.
Further objects, features and advantages of the invention will become apparent from the following detailed description taken in conjunction with the accompanying figures showing illustrative embodiments of the invention.